This is a specialist book, but an important one for economists who would understand the newer methods of trade control. The author's aim is to trace outstanding trends since 1931, with the emphasis on the technique of newer methods. In the first section she outlines the trade controls exercised during the world war, the attempt to get away from them, and the return to them with the depression. She gives a composite picture of world trade through the '20's; then concentrates on the years between 1930 and 1939, when the second world war reversed the processes. She shows the effect of quotas, of mandates, of the barter system, of bilateral agreements, of reciprocal trade agreements. She puts considerable stress on Pan American economic co-operation, indicating the barriers. A useful book in a special field.